For cooling towers and similar heat exchanger installations with high output, heat exchangers with very large heat exchange or accumulator surfaces are necessary. For the economical operation of such heat exchange installations, providing of inexpensive heat exchanger bodies able to be connected side by side and in series in large number is of decisive importance. Numerous attempts have been made to stack together as heat exchanger bodies profiles extruded from plastic which can be produced cheaply. Thus, in West German Published Patent Document DE-OS No. 27 51 115 it is proposed, among many other embodiments, to join, in a stack, extruded hollow chamber panels made of plastic. The chamber panels comprise two plane smooth outer walls and one-piece webs held in place between them by means of an adhesive applied to the outer walls. However, this joining process is too expensive for mass production.